Block 1: Epidemiology
EPI3-8: MEASURES OF EFFECT: INTERPRETING THE RELATIVE RISK

SESSION OBJECTIVE

At the end of this session you should be able to understand the meaning of the magnitude of relative measures of effect (or relative risk) in relation to the number "1" which is the measure of no effect.

LEARNING ACTIVITIES:

There are 3 possibilities for the size of the Relative Risk, RR, relative to baseline or 1 (exposed have the same risk as the unexposed)

RR = 1

RR > 1

RR < 1

In the case of RR = 1, it means that there is no association between exposure and disease.

If RR > 1, there is a positive association which may be causal. We say that exposure "causes" disease.

If RR < 1, there is a negative association which may be causal. We say that exposure "protects" against disease.




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General Introduction to Occupational Health: Occupational Hygiene, Epidemiology & Biostatistics by Prof Jonny Myers is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License
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